BIOL 1001

BIOL 1001 WEEK 5 EXAM WITH ANSWERS • Question 1 2 out of 2 points Which of the following describes natural selection? Correct Answer: d. A population of mammals varies in the length of their legs, water levels rise, and the habitat becomes swampy. The individuals with shorter legs are better able to swim to food, and the population evolves to become shorter-legged. • Question 2 3 out of 3 points As natural selection acts on a population, the amount of variation in the population should: Correct Answer: b. Decrease • Question 3 3 out of 3 points Which of the following is not a way in which the theory of evolution has been supported? Correct Answer: e. None of the above. • Question 4 3 out of 3 points In 1980, only 1% to 5% of all Staphylococcus aureus isolates were MRSA strains. Now 60% to 70% of S. aureus isolates are MRSA strains. This is an example of: Correct Answer: a. Directional selection of bacteria • Question 5 3 out of 3 points In what way is artificial selection different from natural selection? Correct Answer: e. In artificial selection, human preference is the selecting force; in natural selection, environmental conditions are the selecting force. • Question 6 3 out of 3 points The phrase “survival of the fittest” is somewhat misleading because it implies that: Correct Answer: a. The best possible organism will evolve • Question 7 3 out of 3 points A key prediction/implication of evolutionary theory is that: Correct Answer: d. The frequency of alleles in a population changes over time in response to the environment • Question 8 2 out of 2 points Which individuals have the greatest fitness in an area where malaria is common? Correct Answer: e. Individuals heterozygous for the normal and sickle cell anemia alleles • Question 9 2 out of 2 points Your friend was diagnosed with strep throat 2 months ago. She was treated with antibiotics for 10 days, but 2 weeks after treatment, the symptoms returned. She was given a different antibiotic, and her symptoms again initially improved but then got worse. What is happening? Choose the best answer. Correct Answer: c. Your friend was originally infected with bacteria that are resistant to at least two antibiotics. • Question 10 2 out of 2 points A biologist has been studying two populations of trout in Montana for the last 25 years, when the two populations were established from one common population. In the southern population, the fish now have a slightly different mouth shape. But the northern population hasn’t changed from the original type. The new shape works well in catching the type of prey common in the habitat of the southern population. Which explanation is the most likely explanation of the gene differences in the two populations? Correct Answer: d. The gene that produces the variation is probably still present in a small percentage of the northern population, but since there’s no advantage to having it, individuals with the variation aren’t preferentially selected. • Question 11 2 out of 2 points Which of the following occurs after the creation of a new allele? Correct Answer: b. The gene pool becomes more diverse. • Question 12 2 out of 2 points In a population where most of the individuals have long, narrow noses, a child is born with a shorter, broader nose. What’s the most likely explanation for this variation? Correct Answer: a. The child reflects the normal variation around the average type. • Question 13 2 out of 2 points What is the evolutionary origin of light skin in humans? Correct Answer: a. Light skin evolved several times in response to low ultraviolet light levels. • Question 14 3 out of 3 points Which of the following is true of individuals who are well adapted for a particular environment? Correct Answer: c. They may or may not be equally fit in another environment. • Question 15 2 out of 2 points You notice that some squirrels in your neighborhood have a much darker coat color than most of the other squirrels. Is this darker color an adaptation? Correct Answer: b. The trait is only an adaptation if it gives the squirrels an advantage in their habitat. • Question 16 2 out of 2 points Which of the following traits can be acted on by natural selection? Correct Answer: e. All of these can be acted on by natural selection, as long as they’re controlled by genes. • Question 17 3 out of 3 points Two unrelated individuals with the same color skin would: Correct Answer: d. Be no more likely to have similar alleles for any gene that any two individuals chosen randomly • Question 18 3 out of 3 points Choose the best answer. The logic of natural selection predicts that a population of organisms will undergo evolution if, and only if, which of the following condition(s) exist? Correct Answer: d. Both b and c. • Question 19 3 out of 3 points A small founder population of turtles has established a population on an island with a varied and good habitat. There is very little competition between members. What is the likely effect on evolution of this low level of competition? The population will remain very stable in size, and it won’t evolve much. Correct Answer: a. The population will grow in size, and it won’t evolve much. • Question 20 2 out of 2 points What is an allele? Correct Answer: a. A particular version of a gene